.triangulos-box {
    width: 0;
    margin: 2em auto 0;
    background: yellow;
    border: 50px solid;
    border-color: red black;
}

.triangulo-rectangulo {
    width: 0;
    margin: 2em auto 0;
    border: 50px solid red;
    border-top-color: transparent;
    border-right-color: transparent;
}

.triangulo-isosceles {
    width: 0;
    margin: 2em auto 0;
    border: 80px solid red;
    border-top-color: transparent;
    border-right-color: transparent;
    border-left-color: transparent;  
}

.radius {
    width: 200px;
    height: 100px;
    background: yellow;
    margin: 2em auto 0;
    border: 2px solid black;
    border-radius: 30px;
}

.elipse {
    width: 200px;
    height: 100px;
    background: skyblue;
    margin: 2em auto 0;
    border: 2px solid black;
    border-radius: 50%;
}

.figura {
    width: 200px;
    height: 100px;
    background: orange;
    margin: 2em auto 0;
    border: 2px solid black;   
    /* border-radius: 25px / 75px; */
    border-radius:
        120px 120px 10px 10px /
        10px 10px 20px 20px;
}
